This invention relates to a document filing system which sequentially stores picture information on a document etc. in a memory unit and retrieves any desired one, as required, from the various picture information stored to permit it to be read out.
A document filing system has been developed and put to practical use, which reads out picture information on a document etc., currently available in large quantity, through two-dimensional optical scanning, retrieves, and reads out, any desired one, as required, from the various picture information stored, and delivers it to an output unit, such as a CRT display device or a printing device, for display in a viewable state.
In such system, a CRT display device with too large a screen cannot be used due to a restriction on a cost and a space factor. For this reason, the picture information is displayed to a reduced scale which is smaller than the original dimension of a document. By so doing, it is possible to display a whole picture image, corresponding to one page of an A4 sized document, on the screen of a CRT display unit. Since, however, 525 scanning lines are used in the CRT display unit, poor resolution results and, for the small characters on the document, there are cases where it is often impossible to read out such characters as they are.